This invention is directed to a primer compostion and in particular to an electrically conductive and flexible primer composition.
Primer compositions are well known in the art and are widely used in the manufacture of automobiles and trucks as shown in Simon U.S. Pat. No. 4,232,090 issued Nov. 4, 1980. High solids polyester coating compositions also are well known as shown in Chang U.S. Pat. No. 3,994,851 issued Nov. 30, 1976. Polyester compolymers having linear and branched chains useful for coatings are shown in Sommerfeld et al U.S. Pat. No. 4,442,269 issued Apr. 10, 1984. However, none of these compositions meet the current needs of the automotive and truck manufacturing plants
In modern auto and truck manufacturing facilities, the top coat paint is applied by electrostatic spraying which in general has not been done previously. Electrostatic spraying reduces paint loss and air pollution caused by paint over-spraying. To efficiently electrostatically spray a paint, the substrate must be conductive. Most autos and trucks contain flexible plastic components and some auto bodies are constructed entirely from a polymer reinforced fiber glass and others from plastic. Obviously, these components are not electrically conductive and electro-static spraying works poorly under the best conditions. Also, these components are flexible and require a primer and a topcoat that is flexible. There is a great need in auto and truck manufacturing for a high quality primer that is electrically conductive, flexible, has excellent adhesion to the substrate and provides a surface to which conventional coatings will adhere.